CHARLOTTE, N.C. -- Martin Truex Jr. has agreed to an extension to stay in the No. 56 Toyota for Michael Waltrip Racing with NAPA as his primary sponsor, sources told ESPN.com.

MWR has scheduled a press conference for Friday at Atlanta Motor Speedway where Truex and NASCAR president Mike Helton will be present to announce 2013 plans and unveil a car.

Truex, 32, is fifth in the Sprint Cup standings heading into Sunday's race at AMS. His 13 top-10 finishes are his most since 2007, when he had 14 en route to making the Chase for Dale Earnhardt Inc.

Truex, a two-time champion in the Nationwide Series, moved from Earnhardt Ganassi Racing to MWR in 2010. He struggled to 22nd and 18th in the standings his first two years before turning things around in 2012 thanks to a company-wide overhaul.

"He's been amazing," team owner Michael Waltrip told ESPN.com earlier this season when it appeared Truex would re-sign with NAPA as his sponsor. "It's a whole lot about timing. We've got better cars for him to drive. We've got him a championship competition director for him to help organize a plan. We've got wonderful teammates for him.

"All those factors have worked together to inspire Martin and make Martin all that he's ever been."

Truex has made it no secret MWR is where he wants to stay.

"I really never talked to anybody else or even really thought about going anywhere else," Truex said during a recent test at Martinsville Speedway.